Water Heaters vs. Boilers: What’s the Difference?

It’s easy to take hot water for granted, but let’s face it—we need it. There’s only so long you can go without a hot shower, after all. Plus, the dishwasher depends on it, and a bubble bath just isn’t the same without warm water. 

Both boilers and water heaters supply your home with all the hot water you need, but they’re also very different. If you need to choose between the two, consider these points to decide on what would work best for you.

The Main Difference Between Water Heaters and Boilers

There are a handful of big differences between water heaters and boilers that are important to factor into your decision-making.

Water Heater

Water heaters are powered by gas or electricity rather than steam or radiant heat. They won’t provide central heat to your home like their competitor, but that may be right for you if you live in a warm climate year-round. Here are some other unique characteristics of water heaters. 

• Electric or gas-powered

• Water produced is safe to consume

• Doesn’t heat water to boiling

• Doesn’t provide central heating

• Inexpensive materials and installation

Boiler

Unlike water heaters, boilers don’t just heat your water—they also heat your home. While installing a new boiler is roughly twice as expensive as the alternative, they have longer lifespans, which means you could save on replacements in the long run. Here are a few other important distinctions to keep in mind. 

• Steam or radiant heat-powered

• Provides central heating in addition to hot water

• Water is non-potable

• Heats water to near boiling

• Costly installation and materials 

What Is a Boiler?

Boilers provide central heating for your home and hot water to your faucets (talk about two birds with one stone!). Although they can be a bigger investment upfront, they can save you money in the long run. Also remember that a boiler is different from a furnace, despite the term being used interchangeably.

Uses for Boilers

A boiler is used to produce steam or hot water. Some other core functions of boilers include:

• Central heating

• Boiler-based power generation

• Cooking

• Sanitation

Boilers are suitable for residential, commercial, and industrial use. Many homes use a boiler for heating because they are more energy-efficient than a traditional furnace. Boilers are also quieter than a furnace.

Types of Boilers

The two main types of boilers are hot water boilers and steam boilers. Hot water boilers are used to produce hot water for residential and commercial properties. Meanwhile, steam boilers generate steam and are more frequently used in industrial settings. 

Boilers also vary in the amount of pressure they use. Low-pressure boilers produce up to but not more than 15 pounds per square inch (PSI), which equates to roughly 250 degrees F, while high-pressure boilers can reach levels of up to 100 PSI. For residential purposes, low-pressure boilers are almost always favored. 

The cost of your boiler varies according to the size of your home. A new boiler for a standard 1,500 sq. ft. home costs about $5,700 on average.

Boiler Pros

• Heat is evenly distributed

• Less noisy than water heaters

• No vents or forced air that blows allergens and dust

• Typically lasts longer than water heaters

• Costs less to run than forced-air systems

Boiler Cons

• Costs two to three times more than water heaters

• Replacement parts are more costly

• Takes time for temperature to change after adjusting thermostat

• Requires additional ductwork for central cooling system

What Is a Water Heater?

Water heaters have one mission: to provide your house with hot water. It’s definitely one of the first must-have appliances you’ll want to install in a new home.

Uses for Water Heaters

As the name indicates, water heaters heat up water. The water is then used for a variety of purposes, including cleaning, showering, and cooking. A water heater receives cold water from the supply line, heats the water using gas or electricity, and then pumps hot water through whichever outlet you open.

Types of Water Heaters

There are two primary ways to categorize water heaters: by heating source or by type. Gas water heaters are one of the most common and often seen in older homes. Newer homes may have an electric water heater or even a solar one.

A storage water heater, also known as a conventional water heater, comes with a water tank and stores hot water inside. Storage water heaters cost from $600 to $800, and installation can cost anywhere from $900 to $2,500.

Meanwhile, a tankless water heater, also known as an instantaneous water heater, heats water upon demand. Most tankless water heaters are powered by gas because electric models require a high amperage most homes may not be able to provide. Tankless water heaters cost $2,523 on average, and the actual price can vary from $1,329 to $3,717.

Pros

• Less energy to run than boilers

• Smaller in size (tankless)

• Easier to install

• Many different options

• Lower upfront costs

• Less expensive to replace

Cons

• Requires separate system for central heating

• Higher utility bills

• Tankless may require water softener

• Water temperature can be inconsistent

Boiler vs. Water Heater

Boilers and water heaters are significantly different, but how can you choose? If you already have a central heating system, then you’re probably better off installing a water heater. However, if you’re building your house from the ground up, you might benefit from choosing a boiler system.

Options

Standard boilers are designed for heating, but can also run a heating loop through a tank to heat your domestic water efficiently. Combination boilers will perform heating and domestic hot water without the use of a storage tank. 

The main two types of water heaters are tank or tankless. The tank heaters heat the water and hold it in the tank until it’s needed. On the other hand, tankless heaters heat water on demand. They can also use a heat pump or a hybrid heater, which uses 60% less electricity because it uses heat in the air and the ground instead of electricity. If you’re keen on keeping energy costs down, deciding between a water heater with a heat pump and a boiler may be the way to go. 

Most choices: Water heaters

Life Span

Boilers can last 25 years or more, while combination boilers last about 10 to 15 years. Eventually, you’ll notice problems like odd noises, radiators taking a long time to heat, water leaks, or higher gas bills. High-quality boilers that are properly maintained have the best chance of lasting a long time.

Water heaters usually last around six to 10 years, with most carrying a six-year warranty. Notably, if you consider the pros and cons of tankless water heaters, you’ll find that tankless models can last 20 years with a 15-year warranty. Common signs of a failing heater include water leaks, hissing sounds, and inconsistent performance.

Longest life span: Boilers, if you invest in a high-quality model

Price

​Installing a new boiler costs $5,800 on average. A standard-efficiency boiler costs $3,000 to $6,000 and a high-efficiency boiler costs $6,000 to $11,000. Installation costs $1,000 to $2,500 on average, but some installs can reach $5,000.

Replacing a standard gas boiler costs $4,000, and replacing a high-efficiency boiler costs $7,500. These costs include a tank inspection, soil test, tank replacement, old tank disposal, and environmental cleanup.

Additionally, if your boiler is powered by oil, you’ll need to account for periodic oil refilling. 50 gallons of oil could last all winter if your home is less than 1,000 square feet, with 100 gallons costing around $300 to $600. Note that this estimate will fluctuate as global oil prices change.

On the other hand, water heaters cost substantially less. A new water heater costs $1,200 on average with installation. Tankless heaters cost $1,000 to $3,000 while high-efficiency heaters cost $700 to $3,000, and installation ranges from $150 to $1,500.

Most affordable: Water heaters, if you already have a central heat system

Installation

Installing a boiler in your home requires extensive work, especially if you’re putting in a brand-new system. Boilers are very heavy and have many complex parts. You would need to install the boiler, radiator, and the input and output pipes under flooring. For a job like this, it’s probably best to call a boiler installation company near you.

If you have some plumbing knowledge, you may be able to DIY a water heater installation. However, there are many steps involved, and you’ll need some muscle to get it done.

Easiest to install: Water heaters

Repair/DIY-ability​

Generally speaking, if you’re noticing issues with your boiler, like leaks, temperature differences, or emissions problems, you’ll want to call an HVAC professional. Boiler parts are intricate and complex, so repairing them is not a typical DIY project and isn’t recommended if you don’t have the proper certification. Instead, find out who to hire to fix a boiler and reach out to them directly. 

If you call in a pro, you can expect the cost of a boiler repair to fall somewhere between $240 and $2,500.

Water heaters are easier for DIY repairs, depending on the problem. Most DIYers will be able to troubleshoot common issues like temperature being too hot or cold, the pilot light going out, or the heater working less efficiently.

If you have to hire a pro, the cost of a water heater repair ranges from $100 to $1,300.

Easiest to DIY repairs: Water heaters

Maintenance​

Boiler maintenance requires an annual inspection of your boiler, vents, and wiring. Every six months, you should lubricate the circulating pumps, flush, and clean your boiler. Additionally, conduct a safety valve check monthly, and perform 

To maintain your water heater, you should conduct a visual inspection for leaks, test the water valve, and drain the tank to remove sediments.

Easiest to maintain: Water heaters

Sustainability​

Boilers can be considered more sustainable because they harness the natural properties of hot water or steam.

But if you’re looking for something that is 100% sustainable, your only option is a solar water heater. These cost around $1,000 to $6,000 for the tank and $2,000 to $4,000 for installation. Although the upfront costs are high, it’s hard to beat having unlimited hot water without paying for electricity or natural gas.

Additionally, you can opt for high-efficiency tankless water heaters that use less energy.

Most sustainable: Boilers

Water Heater vs. Boiler Installation Cost 

Installing a brand-new boiler costs an average of $5,800 for all the labor and materials involved, though you could pay up to $11,000 or more if you opt for a high-efficiency boiler. By contrast, it costs an average of $1,200 to purchase a new water heater and have it installed, and $3,000 is the most you’ll pay for both tankless and high-efficiency options. 

DIY vs. Hiring a Pro

For new boiler installations, hiring a boiler installer near you is always recommended because of the risks involved. On the flip side, you may be able to install a water heater on your own if you have prior plumbing experience. However, hooking up your machine to either your gas or electricity line can be hazardous, so outsource this job to a pro if you have even the slightest doubt.